The present invention relates to liquid crystal displays, and in particular, to adjusting the display signals in liquid crystal displays.
Unless otherwise indicated herein, the approaches described in this section are not prior art to the claims in this application and are not admitted to be prior art by inclusion in this section.
There are two general markets for video display equipment: the consumer market and the professional market. Professional equipment may be used for activities with higher requirements than consumer equipment, such as for video and film viewing during post-production, editing, broadcasting, etc. A common professional monitor is the model BVM-D24E from Sony Corp., a 24-inch display that costs approximately $25,000. The model BVM-D24E uses a cathode ray tube (CRT).
In recent years, the consumer market has shifted from CRT technology to liquid crystal display (LCD) technology as the cost of LCD equipment has decreased. However, this trend has not penetrated the professional market until recently. For example, Sony Corp. recently discontinued the model BVM-D24E (which has a CRT) and has introduced the model BVM-L230 (which has a LCD), a 22.5-inch display that costs approximately $14,000.
Other companies have also introduced LCD displays in the consumer market. BrightSide Technologies (recently acquired by Dolby Corp.) has developed high dynamic range (HDR) LCD displays. Details of these HDR displays can be found in WO 02/069030 titled “High Dynamic Range Display Devices”, WO 03/077013 titled “High Dynamic Range Display Devices”, and WO 06/010244 titled “Rapid Image Rendering on Dual-Modulator Displays”.
For many LCD displays, power management is an issue. In general, an LCD display includes a backlight layer and an LCD layer. The backlight layer generates light and the LCD layer selectively blocks light. Thus, in an area where the LCDs are blocking light, it is inefficient for the backlight layer to generate more light than is needed. Efficiency of the LCD display may be improved by generating only the necessary amount of light, and no more. One measurement is the average light power, and an average light power of 100% (e.g., a multiplier of 1×) meets the efficiency needs.